Current pH-intelligent sensors are so compact that per unit area can only indicate a small amount of foods. Improving porosity of sensor materials will be an effective way to solve the problem. In this study, sodium alginate (SA) and κ-Carrageenan (κC) were simply cross-linked to produce a porous and water-absorbing aerogel with low density, high porosity and water vapor uptake. Afterwards, Clitoria ternatea anthocyanins were blended with sodium alginate/κ-Carrageenan/Ca